With a staff of more than 3,000, the U. S. Naval Ordnance Laboratory is a major naval research and development activity. Its projects range from the creation of subminiature components to the conception and development of complete weapon systems. In complexity, many NOL facilities rival the weapons that they help develop. In the Hyperballistics Range, seen here, model shapes are fired by a modified 12-inch naval gun into a 1,000-foot-long tunnel to obtain electronic and photographic analyses of their characteristics. Atmospheric pressure in the range may be reduced to simulate any desired altitude, and model velocities of five miles-per-second are attainable. Concave mirrors along the tunnel focus images for shadow-graphs, like that on the preceding two pages. In the high-speed x-ray photograph below, the model is seen separating from the sabot that held it in the gun barrel.
Understandably, an important NOL effort is the development of explosives. A high-speed framing camera, seen at left with its inventor, is the laboratory’s primary means of documenting detonations of explosives. Each of the frames in the series above was exposed for one sixty-millionth of a second. Conventional and nuclear underwater explosions are simulated with the aid of the 30-foot diameter centrifuge below, which is capable of accelerations of 300 G’s. The explosion of a pellet in the centrifuge behaves like a full scale underwater blast. A high-speed series of the oscillating bubble formed in such a test is seen below.
NOL operates six wind tunnels at Mach numbers of from 0.2 to 17. The hypersonic tunnel seen here can be operated continuously at speeds up to Mach 10. At right, a probe is placed in the test section for calibration of the tunnel nozzle. A schlieren photograph, at bottom, shows the shock wave formed by air rushing past a slender cone.
Activities at the Naval Ordnance Laboratory include basic research, applied research, and developmental programs. As part of a basic research program, the x-ray diffraction studies underway at top determine the precise atomic structure of materials. In the field of applied research, a mine under development, above, is prepared for environmental shock tests. At right, as part of a continuing NOL program of determining ship degaussing requirements, a magnetic coil simulates the earth’s magnetic field around a British escort ship model.
The 354-foot unmanned SPAR (Seagoing Platform for Acoustics Research), at left, is operated by NOL out of Solomons, Maryland, one of the Laboratory’s three test facilities. Upended at sea, the SPAR becomes a stable platform for a hydrophone array, top, used in studies of underwater sound propagation. As part of the Navy’s interest in deep submergence, NOL developed the concept of glass-hulled submersibles. The hatch segment of an experimental sphere is seen above, before impact tests.
The behind-the-scenes efforts of more than 1,000 NOL personnel support its overall scientific goal. In the computer section, at left, data from all experiments are reduced to meaningful form. In addition to building and maintaining many NOL facilities, the technical shops machine precision models and wind tunnel nozzles. Computerized boring and milling machinery, like that above, is complemented by old-world craftsmanship, such as the hand-blown glass array seen at top.
In the past ten years, 12 5 weapon systems and ordnance devices have been completed and released to production by NOL. In keeping pace with advancing weapons technology, its facilities are ever-changing. The console seen above monitors a 3-megawatt arc-tunnel, a facility under development at NOL. The largest such wind tunnel in existence, it employs an electric arc to create a true airflow through the test section. Nearing completion is a 1.75 million-gallon hydroballistics tank, at left, which will permit testing of weapon systems in a controlled water environment. With a test capability of velocities of up to 6,000 feet-per- second, and weapon-model scales up to one-fifth full size, this facility will help speed the development of ordnance systems which are still to be created.